From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on inbox.vuxu.org X-Spam-Level: X-Spam-Status: No, score=-0.5 required=5.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,HTML_MESSAGE,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from minnie.tuhs.org (minnie.tuhs.org [45.79.103.53]) by inbox.vuxu.org (OpenSMTPD) with ESMTP id 4d8940a2 for ; Sat, 4 Jan 2020 22:19:54 +0000 (UTC) Received: by minnie.tuhs.org (Postfix, from userid 112) id A55739B542; Sun, 5 Jan 2020 08:19:52 +1000 (AEST) Received: from minnie.tuhs.org (localhost [127.0.0.1]) by minnie.tuhs.org (Postfix) with ESMTP id 6C09D95197; Sun, 5 Jan 2020 08:19:24 +1000 (AEST) Authentication-Results: minnie.tuhs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=jon-es.20150623.gappssmtp.com header.i=@jon-es.20150623.gappssmtp.com header.b="XBiK3loG"; dkim-atps=neutral Received: by minnie.tuhs.org (Postfix, from userid 112) id E888A95170; Sun, 5 Jan 2020 08:19:20 +1000 (AEST) Received: from mail-lj1-f180.google.com (mail-lj1-f180.google.com [209.85.208.180]) by minnie.tuhs.org (Postfix) with ESMTPS id D3CE39516C for ; Sun, 5 Jan 2020 08:19:19 +1000 (AEST) Received: by mail-lj1-f180.google.com with SMTP id j26so47200233ljc.12 for ; Sat, 04 Jan 2020 14:19:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=jon-es.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=u4LwXm4y0sHkc8LQ7lthcCkIq5LVEl1Zkaes0my/HJ4=; b=XBiK3loGHahL/NYhVMXLCh4g9kT5uf5zwt2f0FkMQuixbzJHI7dOPd/A6YblaQmh8H iL8qUGVRUICoKLtrFSYlhgf20iu8l/MozJP1fh8kM4Xom3p/1OxGqy4GlTvDZMoo1Jlb 2YrZCN6w8rpg96kHi2TOesw6XMTYunN0Smgqy9vVgGAwzO7eYr23TAlYWEpzQ5SdhmvG ovSt/uy7nOTVMJmnoNry3XZmAfHJRd8j8tGxyYclLjwqJ/gJET6EoIIWKqKEE90oZ2mN dpnrYW5CAo6G+IQQsBzlByE5RrTRuBS2PSf+/dCVy0++MtJaXlpnqGbvSqGvW+BZxvA/ ox1A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=u4LwXm4y0sHkc8LQ7lthcCkIq5LVEl1Zkaes0my/HJ4=; b=KSn82y3ul0mFJm9X+hmkTeTBGKe3N7QipqTXUs9aGRosvfLQw36esh5X0PKMmdsWMC V+jiikT/YRePguqQbPzPTwT6LJ2SRKr7eljMmzurWW5DqcPMkKZqqipprpljKnniN12C 5OStlMpRtH2Lx4NoeuS50bwIrhj24YYAkr5k0HPoavDghIlOqz3GADM8Ny+rfDpypLWA 6E/oPvJn9PMX5421imEGdojyUA6KmWzYQoail92yyz3e3/GhomtNyvyjHyLcApdXdm17 1Iwag76vvNC6+Ndv3l0SzbFhwzrZcBscJpvulbHUqVnjwZv/hwb6u6dtXdwCfYMTxMC/ nuOQ== X-Gm-Message-State: APjAAAXE9VRgTuqKpe1e5yPhmRgmk8vlR+0aT5XkhyzKMsVxqxdCMK+X CcBjQ3pEkjWoz9D6TjVDaxvn5RGhIwsUs0QYVaI= X-Google-Smtp-Source: APXvYqxpMrrmUifoyzfKVa213ThojyApzBQqhjWMW6RJxSiKQ26bJPNa8wBKjpYolyGPttMmNGl+CdPMO2CZ59RW22o= X-Received: by 2002:a05:651c:111c:: with SMTP id d28mr56711434ljo.32.1578176358271; Sat, 04 Jan 2020 14:19:18 -0800 (PST) MIME-Version: 1.0 References: <202001040258.0042wuic1359237@mail.cs.dartmouth.edu> <1ingL0-5g6-00@marmaro.de> In-Reply-To: From: Terry Jones Date: Sat, 4 Jan 2020 23:19:07 +0100 Message-ID: To: Warner Losh Content-Type: multipart/alternative; boundary="0000000000003a50f1059b57d18b" Subject: Re: [TUHS] sh: cmd | >file X-BeenThere: tuhs@minnie.tuhs.org X-Mailman-Version: 2.1.26 Precedence: list List-Id: The Unix Heritage Society mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: The Eunuchs Hysterical Society Errors-To: tuhs-bounces@minnie.tuhs.org Sender: "TUHS" --0000000000003a50f1059b57d18b Content-Type: text/plain; charset="UTF-8" Was : actually designed for commenting? If so, at what point did it become a command that always returns zero exit status? Was it always built-in, or did it originally have a separate filesystem existence (like "[")? Python has a useful "pass" command, but : is much nicer because you can "comment" out a single command in (e.g.) an if/then and it remains syntactically valid and executable. I find it very elegant. Terry On Sat, Jan 4, 2020 at 10:40 PM Warner Losh wrote: > > > On Sat, Jan 4, 2020, 3:11 PM Dave Horsfall wrote: > >> On Sun, 5 Jan 2020, Dave Horsfall wrote: >> >> > The Unix philosophy, perhaps i.e. keep it simple? Why have ":" (an >> > actual internal Shell command) when "" (the null command) will do the >> > job? >> >> Also, remember that ":" was also used as a comment, before "#" was used. >> > > I thought it was a null label for a goto target... :) > > Warner > > -- Dave >> > --0000000000003a50f1059b57d18b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Was : actually designed for commenting?=C2=A0 If so, = at what point did it become a command that always returns zero exit status?= =C2=A0 Was it always built-in, or did it originally have a separate filesys= tem existence (like "[")? Python has a useful "pass" co= mmand, but : is much nicer because you can "comment" out a single= command in (e.g.) an if/then and it remains syntactically valid and execut= able. I find it very elegant.

Terry
=

On Sat, Jan 4, 2020 at 10:40 PM Warner Losh <imp@bsdimp.com> wrote:


On Sat, Jan 4, 2020,= 3:11 PM Dave Horsfall <dave@horsfall.org> wrote:
On Sun, 5 Jan 2020, Dave Horsfall wrote:

> The Unix philosophy, perhaps i.e. keep it simple?=C2=A0 Why have "= ;:" (an
> actual internal Shell command) when "" (the null command) wi= ll do the
> job?

Also, remember that ":" was also used as a comment, before "= #" was used.

<= div dir=3D"auto">I thought it was a null label for a goto target... :)

Warner

-- Dave
--0000000000003a50f1059b57d18b--